Expulsion fuse holder for high tension electric conductors



May 20 "1941 L F. PARKER :TAL 2,242,921 EXPULSION FUSE HOLDER- FOR HIGH TENSION ELECTRIC CONDUCTORS Filed DEC. 2, 1939 2 Sheets-5h99?. 1

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May zo, 1941. I F. PARKER HAL 2,242,921

EXPULSION FUSE HOLDER FOR HIGH TENSION ELECTRIC CONDUCTORS Filed Dec. 2, 1959 2 Sheets-Sheet 2 ATTORNEY.

Patented May 20, 1941 EXPULSION FUSE HOLDER FOR HIGH TEN- SION ELECTRIC CONDUCTORS Laurie F. Parker, Noroton, and George W. Whitney, Stamford, Conn.

Application December 2, 1939, Serial No. 307,250

(Cl. 20D-127) 1 Claim.

This invention relates to that type of fuse holders, particularly for high tension wires, comprising a fuse box and a cover in combination with means for throwing the cover open when an overload burns a fuse contained within the box, the circuit being broken. The specific object of the invention is to provide means adapted to overcome a difficulty heretofore met with devices of the kind, i. e., arcing and premature fuse burning due to the vibratory action of alternating current.

The invention will be described with reference to the accompanying drawings, in which:

Figure 1 is a sectional elevation showing an embodiment of the device, dotted lines showing the position of the cover when the same is automatically released by the burning of a fuse and the propulsion of the cover by spring means.

Figure 2 is a front elevation 'of the device with the cover removed and certain cover-connecting parts shown in cross section, the view being taken on the line 2-2, Figure 1.

Figure 3 is a horizontal section on the line 3-3, Figure 1.

Figure 4 is a view similar to Figure 1, showing the cover swung down for exposing the fuse.

Figure 5 is a top plan view of the cover, showing the fuse and its supports and connecting members.

Figure 6 is a detailed view of the fuse, partly broken away.

Figure 7 is a longitudinal section fuse head.

Figure 8 is a horizontal section on the line 8 8, Figure 7.

Referring to the drawings, the device comprises a casing I of insulating material such as porcelain or glass and having a cover member 2 formed with a handle 2x. The casing is apertured at Ir for the passage of an electric conductor 3, the exposed wire being clamped in a contact sleeve 4 electrically connected to a single or composite spring plate contact 5.

Casing I is also apertured at Ira: to receive an electrical conductor 6, the wire of which is clamped in the sleeve of a contact bracket 1 having a face 'Irc extending at right angles to the plate contact 5.

The electrical connection between conductors 3 and 6 is effected by means of an expulsion fuse generally indicated at 8 and by certain connections now to be described.

' The contact fuse comprises a cylinder held by cover member 2, the latter being provided with internal apertured bosses at 9 to receive the fuse through the cylinder. Surrounding the fuse cylinder is the sleeve of a bracket I0 at each side of which is a pair of studs, stud entering a slot at |21: in a second and movable bracket member I2 and stud I3 entering a slot at I2.r.r in said movable bracket I2. Bracket I2 is provided with hooks at h to engage pins I4 on a fixed member I4 carried by casing I.

Movable bracket I2 carries a headed spring contact member I5 which may be engaged by a supplemental coiled spring I6, the lower end of which is fastened to a pin I1 carried by movable bracket member I2.

When the cover is closed the movement thereof from open position as shown in Figure 4 to the closed position as shown in Figure 1, will bring the headed contact member I5 into engagement with plate contact 1a: and will move contact spring I5 toward the expulsion fuse 8 against the tension of spring I6 and the contact head of the expulsion fuse will engage contact member 5.

The expulsion fuse is best shown in Figures 6 and '7. It comprises a cylinder within which is an electric cable I8 connected to a, fusible metal strip I9 at the top of which is a head |91'. The end of the tube has swaged thereon a shouldered metallic sleeve 20 (Figure 7) which iss externally threaded at a projecting ring section. Threaded upon sleeve 2U is a collar 2| having an apertured head to receive a floating contact post 22. To hold the post against retraction from collar 2|, the post is headed at its outer end and near its inner end it is channeled to receive a detent spring ring 23.

Cable I8 leading from expulsion fuse is passed under a thumb nut 24 threaded into a face of movable bracket member I2, and thumb nut 24 (which will be carried by a threaded stem) is turned down until the cable is firmly fastened to said bracket I2, and the cable will be drawn taut, exerting a pull upon the head |990 of the fusible member I9. Thus the expulsion fuse and the cover member 2 virtually become rigid attachments of bracket member I2.

With the parts in the position of Figure l, the burning out of the fusible member I9 will release the tight connection between the fusible member and bracket I2 and these members will only be pivotally connected through the studs II and I3. The action of spring I6, and the springiness of the spring contact member I5 will throw the cover to the dotted-line position of Figure 1, the cover carrying with it the fuse cylinder and connected parts.

Thus there Will bev visual indication that the fuse of the particular boX has burned out. The cover may then be swung down to the position of Figure 4 and the required fuse element restored followed by the securing of its cable I8 to movable bracket member l 2 by means of the clamping action of thumb nut or thumb screw 24.

In expulsion fuse devices for A. C. current lines solid head contact cap-s threaded upon the fuse cylinders and engaging the fusible element head when threaded down into hal position have heretofore been employed, the steady and long continued vibratory force of the current has tended to gradually cause rotation of the threadeded sleeve and to release that close contact oi the sleeve head and fusible element required to avoid arcing, and the resulting arc burns out the fuse. By means of the structurev shown in more detail by Figure 7, there is no direct contact between the sleeve 2i and the Contact spring plate 5 andl an independent contact member has a iioating support by and relatively to sleeve 2i, this heatingy Contact head being the member 22. The vibratery force of the alternating current will tend to very gradually cause rotation of the sleeve i and in time this rotation may amount to one cr a plurality of complete turns of the sleeve. This, however, will in no Way affect the retaining of theV floating contact head or post 22, and the device will be maintained free from arcing, the fuse burning only upon an overload.

Having described our invention, what We claim .and desire to secure by Letters Patent, is as follows:

In expulsion fuse holders for electrical conductors, a casing and a, cover therefor, an abutment carried internally of the cover, a headed lfusible element having its head engaging said abutment, spring means for moving one end of the cover away from the casing, an electric conductor cable connected to the headed fusible element and to spring means for restraining the latter against action, through the engagement of the fusible element head with said abutment, a contact carried by the casing, a cap surrounding the headed fusible element and threaded on the abutment and a contact post passing through an aperture in the end of the cap and adapted to be guided by the Walls; of 'Said aperture for endvvise movement relatively to the cap and relatively to the fusible element head, said contact post being adapted to simultaneously engage the headed fusible element and the casing contact and to be held in such relation by the cap, the cap being adapted to move longitudinally of the contact post Without disturbing its operating position.

LAURIE F. PARKER. GEORGE V7. WHITNEY. 

